Rotting Rats is a common Creature — Zombie Rat card from Planechase (HOP), collector number 39. Current market price: $1.59, TCGplayer market prices via Scryfall.
When this creature enters, each player discards a card. Unearth {1}{B} ({1}{B}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)